In a lithography process as one of manufacture processes of devices such as semi-conductor devices, liquid crystal display (LCD) panel and the like, the exposure apparatus is used to transcribe pattern images on a wafer or a glass plate as a substrate applied with a photoresist.
A photolithography as a kind of photo-micromachining technique which forms a micro-pattern on a desired portion of the wafer substrate using a light source refers to a process in which light is passed through a mask having a circuit pattern which it is desired to form on the wafer, and geometric patterns on the mask is transferred to a light-sensitive chemical, i.e., the photoresist.
Conventionally, since an exposure substrate is formed of a flat plate type such as a wafer or a glass plate, a planar-type stage corresponding to the size of the wafer or glass plate is required to perform an exposure work on a large-area substrate. However, a high-precision exposure apparatus is required along with micronization of a circuit pattern due to a trend toward miniaturization and large-capacitance. Thus, a conventional planar-type stage encounters a limitation in coping with such a trend.
Particularly, in the case where the exposure work should be carried out in a vacuum environment, a stage for translation of the wafer or the glass plate should be also applied to the vacuum environment. However, since most of stages for use in the vacuum environment use a contact-type mechanical bearing, there is a limitation in making high precision of the exposure apparatus possible due to friction. In addition, even a non-contact type air levitation bearing applicable to the vacuum environment entails a problem in that it can be applied to only a low-vacuum environment.